Drill bit



Aug. 27, 1940. C, H BLACK 2,212,727

DRILL BIT Filed Oct. l2, 1959 @Hom/? Patented Aug. 27. 1940 h A UNITEDSTATES PATENT OFFICQ DRILL BIT Clarence H. Black, Houston, Tex.,assigner to Reed Roller Bit Company, Houston, Tex., a corporation ofTexas.

Application October 12, 1939, Serial No. 299,088

4 Claims. (Cl. 255--71) This invention pertains to drill bits, and morefirm, unbreakable joint between the shaft secparticularly to those inwhich cross-cutters are tions. mounted on a transverse shaft at theforward end In assembling, one of the cutters, such as it, of the bit.is placed on its shaft section I3 and the bridge In bits of this type itis obvious that strength is tted in place. The other shaft section i3. 5and rigidity of the roller shaft are of prime imupon which the cutter I6has previously been portance, and such qualities are best achieved byplaced, is then fitted into the collar so that the making the shaftintegral with the depending projections I Il and It t together and thepin legs which support it. This construction, hcwf 20 is pushed into thehole I5, I li and welded 10 ever, creates the problem of joinder betweentwo therein, and the legs I2, I 2 are welded in place l. i

sections of shaft, since the shaft must be made in 0n the bit head I I.By these means I produce a two pieces to permit the rollers to be placedtherebit with a firm and rigid cross cutter shaft. on. Various types ofjoints have been utilized Although a preferred embodiment of my inforthis purpose, but, so far as I am aware, no one vention is describedabove, I do not wish to be has developed a joint in a structure of thiskind limited thereto, but only by the scope of the apl5 embodying thefeatures of my invention, by which pended claims. firm rigidity anddurability in the cross cutter I claimt shaft are attained. 1- In adrill bit, depending less, a shaft section The object of this inventionis to increase the carried by each leg, roller cutters mounted on thestrength and durability of cross cutter shafts in shaft sections, and ajoinder -structurc for the ""0 drill bits. sections comprising coactingoverlapping projec- This and other objects I accomplish by my intions onthe sections which fit together to form a vention, one specific exampleof which is shown CylindriCal Surface, ODDOSltf-ly disposed @Caching inthe accompanying drawing and fully described channels in the abuttingsurfaces of the sections hereinafter. forming a transverse hole partlyin each shaft 95 Further objects and features will become evisection, apin in the hole to hold the two sections dent from the followingdisclosure when taken in together, and a member having an openingthereconnection with the accompanying drawing, in in embracing theprojections to prevent them which: from separating laterally. Fig. 1 isa side elevation, partly in crosssection, 2. In a drill bit, dependinglegs, ashaft section 30 of a drill-bit utilizing my invention, andcarried by each leg, roller cutters mounted on the Fig. 2 is across-section taken along the line shaft sections, and a joinderstructure for the 2 2 of Fig. 1. sections comprising coactingoverlapping semi- Referring to the drawing in'detail, a drill bitcylindrical projections, oppositely disposed co- 5 head I I has, weldedthereto, depending legs I2, acting channels in the abutting flatsurfaces of 35 I2. Made integral with these legs are sections theprojections forming a transverse hole partly I3, I3' of the cross cuttershaft, and the ends of in each shaft section, a pin in the hole to holdthe these sections are formed with interlocking protwo sectionstogether, and a member having an jections I4, I4 (see Fig. 2) whichcoact as shown opening therein embracing the projections to pre- 40 toproduce a smooth cylindrical joint. Formed vent them from separatinglaterally. 40 in the abutting sides of these projections are 3. In adrill bit, depending legs, a shaft sectapered channels I5, I5' whichform therebetween tion carried by each leg, roller cutters mounted atapered hole of circular cross-section transon the shaft sections, and ajoinder structure for versely through the shaft. the sections comprisingenacting overlapping pro- Cutters I6, I6' are rotatably mounted on thejections semi-circular in cross-section,opposite1y 45 shaft sections I3,I3 and are separated by a disposed coacting channels in the abuttingfiat bridge I 'l which extends between the usual side surfaces of theprojections forming a transverse cutters I1 and has an aperture thereinembrachole partly in each shaft section, a member having the shaft atits place of joinder. This bridge ing an opening therein embracing theprojections,

has an aperture I8 and a socket I9 which are apertures in said memberadapted to register with 50 adapted to register with the top and bottomof the ends of the hole, and a pin inserted in the the hole I5, I5respectively, and a tapered pin apertures and through the hole to holdthe two 2U is fitted -through the aperture I8 and the hole sectionstogether.

I5, I5 and into the socket I9. The pin is welded 4. In a drill bit,depending legs, a shaft section in the aperture I 8 a's shown at 2l toproduce a made integral with each leg, roller cutters mounttures in saidmember adapted to register with the ends of the hole, a pin welded inthe apertures and extending through the hole to hold the two sectionstogether, said member being o a width to space said roller cutters sothat they rotate between the legs and the member.

CLARENCE H. BLACK.

